1. Technical Field
The present disclosure relates to electrosurgical apparatuses, systems and methods. More particularly, the present disclosure is directed to predictive signal processing of electrosurgical generator control signals to alter operational treatment modes during a given RF activation period.
2. Background of Related Art
Energy-based tissue treatment is well known in the art. Various types of energy (e.g., electrical, ultrasonic, microwave, cryo, heat, laser, etc.) are applied to tissue to achieve a desired result. Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, ablate, coagulate or seal tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator.
Ablation is most commonly a monopolar procedure that is particularly useful in the field of cancer treatment, where one or more RF ablation needle electrodes (usually of elongated cylindrical geometry) are inserted into a living body. A typical form of such needle electrodes incorporates an insulated sheath from which an exposed (uninsulated) tip extends. When an RF energy is provided between the return electrode and the inserted ablation electrode, RF current flows from the needle electrode through the body. Typically, the current density is very high near the tip of the needle electrode, which tends to heat and destroy surrounding tissue.
In bipolar electrosurgery, one of the electrodes of the hand-held instrument functions as the active electrode and the other as the return electrode. The return electrode is placed in close proximity to the active electrode such that an electrical circuit is formed between the two electrodes (e.g., electrosurgical forceps). In this manner, the applied electrical current is limited to the body tissue positioned between the electrodes. When the electrodes are sufficiently separated from one another, the electrical circuit is open and thus inadvertent contact with body tissue with either of the separated electrodes does not cause current to flow.
Conventional electrosurgical generators operate in one operational mode (e.g., cutting, coagulation, spray, etc.) which is set prior to commencement of the procedure during a given activation period. If during treatment a need arises to switch from one mode to another, such as during a cutting procedure when a vessel is cut and begins to bleed, the first mode (e.g., cutting) is terminated manually and the second mode (e.g., coagulation) is switched on. There is a need for an electrosurgical generator which can automatically switch among a plurality of operational modes in real time in response to sensed tissue and/or energy feedback signals.